Putting the squeeze on sand will expand understanding of soil mechanics

Mechanics of Granular Materials

Putting the squeeze on sand will
expand understanding of soil mechanics

January 6, 1998: What
do a brick of vacuum-packed coffee, land under houses in San Francisco,
powdered makeup, and tire tracks on Mars have in common?

They all behave according to laws of granular materials which we don't
yet fully understand. To get a better grip on what happens when the ground
shifts - under a house during an earthquake, or under the wheels of a rover
exploring Mars - NASA this month will refly the Mechanics of Granular Materials
(MGM) experiment to expand investigations started on STS-79
in 1996. On STS-89,
scheduled for launch Jan. 22, MGM will run twice as many tests as it did
in its first flight, and under a new range of experimental conditions.

Knowledge from the MGM experiments will be applied in virtually any field
that involves powders or granular materials, including the manufacture of
pharmaceuticals and cosmetics, mining, land conservation and management,
and planetary exploration.

While scientists have experimented with soil mechanics for decades, some
aspects remain out of reach on Earth. The behavior of soils under low-confining
pressures, where the soil acts like a liquid, is difficult to study under
1-g conditions on Earth. Under the low-g conditions of space, MGM provides
a new range of test conditions, including conditions like those experienced
by some soils during an earthquake.